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Neutral Ni and Au Alkyl Substituted Bis-Thiophenedithiolene Complexes


ES 4

Neutral bisdithiolene complexes are still rare in spite of a large interest as components for electric and magnetic materials. The gold and nickel complexes of tert-butyl and diisopropyl substituted thiophenedithiolate ligand, [M(α-tb-tpdt)2] and [M(α-dp-tpdt)2], were prepared and characterized in both neutral and monoanionic forms. The neutral species are more accessible than in the related non-substituted thiophenedithiolates and present fair solubility in common solvents. The radical neutral complex [Au(α-tb-tpdt)2]0 presents a ligand asymmetry indicative of unpaired electron localization in one ligand at variance with [Au(α-dp-tpdt)2] that is fully symmetric, offering a good illustrating the role of the intermolecular interactions in the stabilization of SOMO…SOMO interactions. While in [Au(α-tb-tpdt)2] the significant intermolecular interaction leads to diamagnetic dimers, in [Au(α-dp-tpdt)2] the bulkier substituents by preventing the intermolecular interactions, leads to a regular stacking of molecules and to antiferromagnetic chains that undergoes an AFM transition at ca. 25 K.